Ofcom has not done enough to fix the persistent problems of silent calls, limited competition among landline providers and the difficulties surrounding consumer switching, according to a report.

Margaret Hodge, the Labour MP who chairs the Public Accounts Committee, also said the communications regulator must do more to allow taxpayers and companies that fund it to judge its performance, adding that it was currently impossible to assess if it was providing value for money.

A report by the public accounts committee found an "overall positive picture" of a competitive communications market, which was functioning well and providing customers with choice and low prices.

But there was scope for Ofcom to "do more" to tackle the volume of silent calls, relatively low levels of switching between telecoms providers and limited competition in fixed-line telephony.

The regulator also needed to do more to demonstrate its focus on value for money and explain its intended outcomes, how it would achieve them and how it measured its success.

Ofcom's operating expenditure in 2009-10 was £122 million, funded through broadcast licence fees and charges and grants-in-aid of £75.5 million from the Department for Business, Innovation and Skills and £0.6 million from the Department for Culture, Media and Sport.

Mrs Hodge said: "The communications market is in most cases working well and consumers are enjoying the benefits of competition, such as the ability to choose among good-quality goods and services, and falling prices. Customer satisfaction levels are generally high.

"However, we are concerned that Ofcom has not done enough to deal with such persistent problems as silent calls, the difficulty of switching telecom provider, and the limited competition in the fixed-line telephony market."

She added: "Ofcom also needs to do more to allow the taxpayers and companies that fund its activities to judge its performance. It does publish a lot of information about the consumer outcomes it desires, but does not say how it will measure whether it has achieved these outcomes. It does not tell us what success would look like. This makes it impossible to assess whether it is achieving value for money."

An Ofcom spokesman said: "On silent calls Ofcom called on Parliament for higher penalties which have just been granted. Ofcom will continue its drive to tackle this issue. On fixed-line telecoms we are surprised by the remark about competition. In six years Ofcom - through regulatory intervention - has helped create one of the most competitive telecoms markets in Europe."